Regensburg 2013 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 67: Focus Session (Posters): Crystalline n-type semiconducting oxides - SnO2, Ga2O3, and In2O3 for novel devices
HL 67.10: Poster
Wednesday, March 13, 2013, 16:00–20:00, Poster A
The Seebeck coefficient of In2O3 - Inferences on causes of unintentional conductivity and electron effective mass — Natalie Preissler1, •Oliver Bierwagen1,2, Ashok T. Ramu2, and James S. Speck2 — 1Paul-Drude-Institut, Berlin, Germany — 2University of California, Santa Barbara, USA
If synthesized with high quality and purity, In2O3 along with SnO2 and Ga2O3 can become true wide band gap semiconductors in their own right, allowing new applications such as transparent electronics or power electronics. A long standing issue with these oxides is the source of the unintentional n-type conductivity, and the more recent suspicion that the In2O3 surface dominate the thin film conductivity. Furthermore, literature values on the electron effective mass show a large spread. In this contribution we measured and modeled the room temperature Seebeck coefficient of high-quality, plasma-assisted molecular-beam-epitaxy-grown In2O3 for a wide range of electron concentrations, including the previously unexplored non-degenerate regime. We then use Hall and Seebeck measurements to (1.) confirm the bulk nature (and not the surface) of the unintentionally doped electron system in In2O3, and (2.) estimate the electron effective mass.